The present invention relates to a printing sheet used in a stamp.
As disclosed in Japanese Provisional Patent Publication Nos. 8-118771 and 8-207409, there is a type of stamp using a porous printing sheet in which ink can be impregnated. A pattern is formed on a surface of the printing sheet, including a print portion which allows the permeation of ink and a non-print portion which block the permeation of ink.
On using the stamp, a user holds the stamp and forces the stamp to a media (such as a paper) so that the surface of the printing sheet is urged against the media. With this, ink impregnated in the printing sheet is permeated through the print portion of the printing sheet and transferred onto the media. Therefore, it is possible to repeatedly print images on the media for several times without supplying ink to the printing sheet.
In order to reduce the cost for producing the printing sheet, the conventional printing sheet is made thin. Thus, when ink is impregnated in the printing sheet, the printing sheet may be swollen. In such case, a surface of the printing sheet may be deformed, which causes the printed image to be blurred.
Further, since the printing sheet is made thin, an amount of ink to be impregnated in the printing sheet is relatively small. Thus, it is necessary to further provide a sponge-like member in the stamp. Accordingly, the number of parts of the stamp is increased and the producing cost thereof is also increased. In order to increase an amount of ink to be impregnated in the printing sheet, it is alternatively possible to make the printing sheet thicker. However, since the pores of the printing sheet are generally minute, the time required to fully impregnate ink in the printing sheet becomes longer as the printing sheet becomes thicker.
Furthermore, if the printing sheet is made thin, the elasticity thereof is relatively small. Accordingly, when the printing sheet is urged onto the media, a pressure distribution of the printing sheet may not be uniform. In order to solve this problem, it is necessary to further provide a cushion member in the stamp. Thus, the number of parts is increased and the producing cost thereof is also increased.
Therefore, the first object of the present invention is to prevent a deformation of a surface of a printing sheet. The second object of the present invention is to increase an amount of ink impregnated in the printing sheet without increasing the number of parts. The third object of the present invention is to make a pressure distribution of the printing sheet uniform.
According to one aspect of the present invention, there is provided a printing sheet including (1) a porous layer in which ink can be impregnated and (2) a fibrous layer made of fibers. The fibrous layer is provided to one side of the porous layer. The porous layer carries a pattern on a surface thereof. The pattern includes a non-print portion which blocks the permeation of the ink and a print portion which allows the permeation of the ink.
When such printing sheet is used to form image, the printing sheet is mounted to a stamp. The user holds the stamp and forces the stamp to a media (such as a paper) so that the surface of the porous layer is urged against the surface of the media. Ink (impregnated at least in the porous layer) permeates the printing portion of the porous layer, and is transferred onto the media. Thus, image is formed on the media.
In order to accomplish the first object of the present invention, the fibrous layer is so constructed as to prevent a deformation of the porous layer. With such an arrangement, even if the printing sheet is swollen, a surface of the printing sheet is not deformed. Thus, it is prevented that the printed image (on a media) is blurred.
In order to accomplish the second object of the present invention, the fibrous layer is so constituted that ink can be impregnated therein. With such an arrangement, an amount of ink to be impregnated in the printing sheet can be increased, without providing a sponge-like member or the like. Further, since it is no longer necessary to make the printing sheet thicker (for increasing the amount of impregnated ink), the time required to fully impregnate ink throughout the printing sheet does not become long.
In order to accomplish the third object of the present invention, the fibrous layer has a certain elasticity. With such an arrangement, a pressure distribution of the printing sheet (when the printing sheet is urged onto the media) is uniform, even if the porous layer is relatively thin.
Preferably, the fibrous layer includes one of a non-woven fabric and a textile having raised fabrics. In case where the porous layer includes a foamed resin, it is preferred that the foamed resin of the porous layer and the fabric of the fibrous layer entangle with each other.
According to another aspect of the present invention, there is provided a base sheet (used to produce the printing sheet) including a porous layer in which ink can be impregnated and a fibrous layer made of fibers. A pattern can be formed on a surface of the porous layer, by heating the surface according to desired image.